The development and validation of a Quality of Life questionnaire for those with Inducible Laryngeal Obstruction

Abstract

Inducible Laryngeal Obstruction (ILO), also known as Vocal Cord Dysfunction is a medical condition where the vocal cords adduct, causing significant difficulties with breathing and speaking. There are no current disease-specific psychological outcome measures for assessing experienced distress and impact upon quality of life for those with ILO. This research provides preliminary findings assessing the reliability and validity of a Inducible Laryngeal Obstruction Quality of Life (ILOQoL) questionnaire. This research included item refinement and psychometric validation. Item refinement involved cognitive debriefing, which was undertaken with ten participants. Psychometric validation was undertaken with 31 participants diagnosed with ILO, who were six months’ post discharge from Speech and Language Therapy. Participants were posted a questionnaire pack which included a ILOQoL, Depression Anxiety Stress Scales, the activities sub-section of the Mini Asthma Quality of Life Questionnaire and the Vocal Cord Dysfunction Questionnaire. Two weeks later the same questionnaire pack was repeated, along with a Global Assessment Rating Scale. The ILOQoL demonstrated adequate psychometric properties. The questionnaire had strong internal consistency (α = >.07 for each sub-scale total and overall ILOQoL total), weak convergent validity (p = .05 for two subscales and overall ILOQoL total). Additionally, the questionnaire had strong content validity and no floor or ceiling effects. These preliminary findings indicate that the ILOQoL has the potential to be used as a routine outcome measure during therapeutic interventions by measuring QoL.